This application relates to the art of pipe joints and, more particularly, to pipe joints that use a coupling member for joining together end portions on a pair of pipes. The invention is particularly applicable for use in connecting metal pipes and will be described with particular reference thereto. However, it will be appreciated that the invention has broader aspects and that certain features thereof may be used with other types of pipe.
A pipe joint includes a coupling member having an internally threaded first end portion and an opposite end portion with a pair of axially-spaced internal circumferential grooves therein. An internal shoulder within the opposite end portion is spaced toward the internally threaded end portion from the pair of internal grooves. The internal groove that is closest to the shoulder is a sealing ring groove and the other groove is a spline receiving groove.
The coupling member is used with cylindrical pipe having an externally threaded first end portion and an opposite second end portion with an external circumferential groove therein. The threaded end portion of a pipe is received within the internally threaded end portion of the coupling member. The opposite second end portion of another pipe is received within the opposite end portion of the coupling member. The spline receiving external groove in the pipe end portion is aligned with the internal spline receiving groove in the coupling member, and a spline is inserted therein through a transverse hole in the coupling member to lock the second pipe end portion within the coupling member.
The flexible spline advantageously may be a flexible shaft having at least one layer of helically coiled metal wire. This type of spline provides the flexibility required for insertion into the aligned grooves in the pipe and coupling while providing high shear strength to maintain joint integrity and joint strength.
External indicia is provided on the second end portion of the pipe for indicating when the pipe end portion is fully seated within the coupling member to insure that the spline receiving grooves are aligned.
It is a principal object of the present invention to provide an improved coupling member for joining together end portions of a pair of pipes.
It is an additional object of the invention to provide an improved joint between a pair of pipes.
It is a further object of the invention to provide an improved metal pipe joint that uses a flexible metal spline having high shear strength.
It is another object of the invention to provide a pipe joint and coupling member that are relatively economical and easy to manufacture and assemble.